Hello all. I am new around here and new to the vintage Honda motorcycle experience . I picked up a 67 CB77 (superhawk 300) as a new project but realized upon bringing it home it does not charge. Now motor work and electrical are not my huge strong point , I am more of the fabricating / metal work guy . It looks like the previous owner replaced the voltage regulator with a Chinese scooter unit so that could be an issue . I did pull the stator out and inspect / clean it and from the little I know it looks to be in good shape. I tested the voltage from the disconnected stator wires with the bike running and did not get any + voltage readings from any of the 3 .
Basically I need help being pointed in the right direction to solve this problem. I will take a couple pics and post them momentarily .
Charging system problem , bad stator perhaps ?What was wired in was probably a regulator/rectifier which is not necessarily bad. It could possibly work.
However no AC voltage from the alternator may be a problem. You should get AC voltage between the brown and yellow wire and the brown and pink wire (in the headlight). Check the wires coming out of the stator - They plug into the wire loom.. Make sure it is plugged in and the connections are clean and tight. You should see around 10VAC at idle going up to 40/50VAC as engine RPM goes up. You can also check the OHM reading between the brown/yellow and brown/pink. Should be 2 OHM's or less. Also check for continuity between the wires and the case - Should be none. These bike came with no voltage regulator sometimes resulting in minimum charge or overcharge to the battery. I am sure the piece wired in was a regulator/rectifier which could be used to eliminate this problem. Ok I shall test that . when I tested it I tested from the wires coming out of the stator while they were unplugged from the rest of the harness . Is there any other signs of a bad stator I could check for ? Like I said I didnt see any apparent physical damage but then I dont know what exactly to look for . also when you say test and I should see 10VAC at what point should I test at ? Battery , the wire connection itself , etc. With the stator unplugged from the wire loom (either at the stator leads or the plug at the rectifier) at idle you should see about 10VAC between the brown (common) and yellow wire and the brown and pink wire. As engine RPM increases the voltage should go up to somewhere around 40/50VAC. Note voltage should be about the same for both wires.
Checking the resistance (OHMS) across the wires can give you an idea of condition. Frequently a failed stator will have obvious burn marks. If you are testing at the battery you are looking for DC volts. Check battery voltage, engine off. Then start the engine and check voltage at idle then increase RPM and see is it goes up. Normally a fully charged battery will show 12.5/12.7 VDC. The problem is in normal running (headlight off) you are only getting 1/3 of the alternator capacity. Once the headlight is on the other 2/3 of the alternator (pink wire) is tied in. If you remove the headlight bulb and switch to headlight ON you will see maximum alternator capacity. You would like to see more than 13VDC and not more than about 14.5VDC at about 3000 RPM.
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